bus: rework message handlers to always take an error argument

Message handler callbacks can be simplified drastically if the
dispatcher automatically replies to method calls if errors are returned.

Thus: add an sd_bus_error argument to all message handlers. When we
dispatch a message handler and it returns negative or a set sd_bus_error
we send this as message error back to the client. This means errors
returned by handlers by default are given back to clients instead of
rippling all the way up to the event loop, which is desirable to make
things robust.

As a side-effect we can now easily turn the SELinux checks into normal
function calls, since the method call dispatcher will generate the right
error replies automatically now.

Also, make sure we always pass the error structure to all property and
method handlers as last argument to follow the usual style of passing
variables for return values as last argument.

1 files changed, 237 insertions, 238 deletions

diff --git a/src/login/logind-dbus.c b/src/login/logind-dbus.c
index 984235c4e5..b1c2ef19b1 100644
--- a/src/login/logind-dbus.c
+++ b/src/login/logind-dbus.c
@@ -48,8 +48,8 @@ static int property_get_idle_hint(
                 const char *interface,
                 const char *property,
                 sd_bus_message *reply,
-                sd_bus_error *error,
-                void *userdata) {
+                void *userdata,
+                sd_bus_error *error) {
 
         Manager *m = userdata;
 
@@ -66,8 +66,8 @@ static int property_get_idle_since_hint(
                 const char *interface,
                 const char *property,
                 sd_bus_message *reply,
-                sd_bus_error *error,
-                void *userdata) {
+                void *userdata,
+                sd_bus_error *error) {
 
         Manager *m = userdata;
         dual_timestamp t;
@@ -87,8 +87,8 @@ static int property_get_inhibited(
                 const char *interface,
                 const char *property,
                 sd_bus_message *reply,
-                sd_bus_error *error,
-                void *userdata) {
+                void *userdata,
+                sd_bus_error *error) {
 
         Manager *m = userdata;
         InhibitWhat w;
@@ -108,8 +108,8 @@ static int property_get_preparing(
                 const char *interface,
                 const char *property,
                 sd_bus_message *reply,
-                sd_bus_error *error,
-                void *userdata) {
+                void *userdata,
+                sd_bus_error *error) {
 
         Manager *m = userdata;
         bool b;
@@ -128,7 +128,7 @@ static int property_get_preparing(
 
 static BUS_DEFINE_PROPERTY_GET_ENUM(property_get_handle_action, handle_action, HandleAction);
 
-static int method_get_session(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_get_session(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         _cleanup_free_ char *p = NULL;
         Manager *m = userdata;
         const char *name;
@@ -141,20 +141,20 @@ static int method_get_session(sd_bus *bus, sd_bus_message *message, void *userda
 
         r = sd_bus_message_read(message, "s", &name);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         session = hashmap_get(m->sessions, name);
         if (!session)
-                return sd_bus_reply_method_errorf(message, BUS_ERROR_NO_SUCH_SESSION, "No session '%s' known", name);
+                return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_SESSION, "No session '%s' known", name);
 
         p = session_bus_path(session);
         if (!p)
-                return sd_bus_reply_method_errno(message, -ENOMEM, NULL);
+                return -ENOMEM;
 
         return sd_bus_reply_method_return(message, "o", p);
 }
 
-static int method_get_session_by_pid(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_get_session_by_pid(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         _cleanup_free_ char *p = NULL;
         Session *session = NULL;
         Manager *m = userdata;
@@ -169,28 +169,28 @@ static int method_get_session_by_pid(sd_bus *bus, sd_bus_message *message, void
 
         r = sd_bus_message_read(message, "u", &pid);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         if (pid == 0) {
                 r = sd_bus_get_owner_pid(bus, sd_bus_message_get_sender(message), &pid);
                 if (r < 0)
-                        return sd_bus_reply_method_errno(message, r, NULL);
+                        return r;
         }
 
         r = manager_get_session_by_pid(m, pid, &session);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
         if (!session)
-                return sd_bus_reply_method_errorf(message, BUS_ERROR_NO_SESSION_FOR_PID, "PID %lu does not belong to any known session", (unsigned long) pid);
+                return sd_bus_error_setf(error, BUS_ERROR_NO_SESSION_FOR_PID, "PID %lu does not belong to any known session", (unsigned long) pid);
 
         p = session_bus_path(session);
         if (!p)
-                return sd_bus_reply_method_errno(message, ENOMEM, NULL);
+                return -ENOMEM;
 
         return sd_bus_reply_method_return(message, "o", p);
 }
 
-static int method_get_user(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_get_user(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         _cleanup_free_ char *p = NULL;
         Manager *m = userdata;
         uint32_t uid;
@@ -203,20 +203,20 @@ static int method_get_user(sd_bus *bus, sd_bus_message *message, void *userdata)
 
         r = sd_bus_message_read(message, "u", &uid);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         user = hashmap_get(m->users, ULONG_TO_PTR((unsigned long) uid));
         if (!user)
-                return sd_bus_reply_method_errorf(message, BUS_ERROR_NO_SUCH_USER, "No user '%lu' known or logged in", (unsigned long) uid);
+                return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_USER, "No user '%lu' known or logged in", (unsigned long) uid);
 
         p = user_bus_path(user);
         if (!p)
-                return sd_bus_reply_method_errno(message, -ENOMEM, NULL);
+                return -ENOMEM;
 
         return sd_bus_reply_method_return(message, "o", p);
 }
 
-static int method_get_user_by_pid(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_get_user_by_pid(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         _cleanup_free_ char *p = NULL;
         Manager *m = userdata;
         User *user = NULL;
@@ -231,28 +231,28 @@ static int method_get_user_by_pid(sd_bus *bus, sd_bus_message *message, void *us
 
         r = sd_bus_message_read(message, "u", &pid);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         if (pid == 0) {
                 r = sd_bus_get_owner_pid(bus, sd_bus_message_get_sender(message), &pid);
                 if (r < 0)
-                        return sd_bus_reply_method_errno(message, r, NULL);
+                        return r;
         }
 
         r = manager_get_user_by_pid(m, pid, &user);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
         if (!user)
-                return sd_bus_reply_method_errorf(message, BUS_ERROR_NO_USER_FOR_PID, "PID %lu does not belong to any known or logged in user", (unsigned long) pid);
+                return sd_bus_error_setf(error, BUS_ERROR_NO_USER_FOR_PID, "PID %lu does not belong to any known or logged in user", (unsigned long) pid);
 
         p = user_bus_path(user);
         if (!p)
-                return sd_bus_reply_method_errno(message, -ENOMEM, NULL);
+                return -ENOMEM;
 
         return sd_bus_reply_method_return(message, "o", p);
 }
 
-static int method_get_seat(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_get_seat(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         _cleanup_free_ char *p = NULL;
         Manager *m = userdata;
         const char *name;
@@ -265,20 +265,20 @@ static int method_get_seat(sd_bus *bus, sd_bus_message *message, void *userdata)
 
         r = sd_bus_message_read(message, "s", &name);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         seat = hashmap_get(m->seats, name);
         if (!seat)
-                return sd_bus_reply_method_errorf(message, BUS_ERROR_NO_SUCH_SEAT, "No seat '%s' known", name);
+                return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_SEAT, "No seat '%s' known", name);
 
         p = seat_bus_path(seat);
         if (!p)
-                return sd_bus_reply_method_errno(message, -ENOMEM, NULL);
+                return -ENOMEM;
 
         return sd_bus_reply_method_return(message, "o", p);
 }
 
-static int method_list_sessions(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_list_sessions(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
         Manager *m = userdata;
         Session *session;
@@ -291,18 +291,18 @@ static int method_list_sessions(sd_bus *bus, sd_bus_message *message, void *user
 
         r = sd_bus_message_new_method_return(message, &reply);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         r = sd_bus_message_open_container(reply, 'a', "(susso)");
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         HASHMAP_FOREACH(session, m->sessions, i) {
                 _cleanup_free_ char *p = NULL;
 
                 p = session_bus_path(session);
                 if (!p)
-                        return sd_bus_reply_method_errno(message, -ENOMEM, NULL);
+                        return -ENOMEM;
 
                 r = sd_bus_message_append(reply, "(susso)",
                                           session->id,
@@ -311,17 +311,17 @@ static int method_list_sessions(sd_bus *bus, sd_bus_message *message, void *user
                                           session->seat ? session->seat->id : "",
                                           p);
                 if (r < 0)
-                        return sd_bus_reply_method_errno(message, r, NULL);
+                        return r;
         }
 
         r = sd_bus_message_close_container(reply);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         return sd_bus_send(bus, reply, NULL);
 }
 
-static int method_list_users(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_list_users(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
         Manager *m = userdata;
         User *user;
@@ -334,35 +334,35 @@ static int method_list_users(sd_bus *bus, sd_bus_message *message, void *userdat
 
         r = sd_bus_message_new_method_return(message, &reply);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         r = sd_bus_message_open_container(reply, 'a', "(uso)");
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         HASHMAP_FOREACH(user, m->users, i) {
                 _cleanup_free_ char *p = NULL;
 
                 p = user_bus_path(user);
                 if (!p)
-                        return sd_bus_reply_method_errno(message, -ENOMEM, NULL);
+                        return -ENOMEM;
 
                 r = sd_bus_message_append(reply, "(uso)",
                                           (uint32_t) user->uid,
                                           user->name,
                                           p);
                 if (r < 0)
-                        return sd_bus_reply_method_errno(message, r, NULL);
+                        return r;
         }
 
         r = sd_bus_message_close_container(reply);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         return sd_bus_send(bus, reply, NULL);
 }
 
-static int method_list_seats(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_list_seats(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
         Manager *m = userdata;
         Seat *seat;
@@ -375,32 +375,32 @@ static int method_list_seats(sd_bus *bus, sd_bus_message *message, void *userdat
 
         r = sd_bus_message_new_method_return(message, &reply);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         r = sd_bus_message_open_container(reply, 'a', "(so)");
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         HASHMAP_FOREACH(seat, m->seats, i) {
                 _cleanup_free_ char *p = NULL;
 
                 p = seat_bus_path(seat);
                 if (!p)
-                        return sd_bus_reply_method_errno(message, -ENOMEM, NULL);
+                        return -ENOMEM;
 
                 r = sd_bus_message_append(reply, "(so)", seat->id, p);
                 if (r < 0)
-                        return sd_bus_reply_method_errno(message, r, NULL);
+                        return r;
         }
 
         r = sd_bus_message_close_container(reply);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         return sd_bus_send(bus, reply, NULL);
 }
 
-static int method_list_inhibitors(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_list_inhibitors(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
         Manager *m = userdata;
         Inhibitor *inhibitor;
@@ -409,11 +409,11 @@ static int method_list_inhibitors(sd_bus *bus, sd_bus_message *message, void *us
 
         r = sd_bus_message_new_method_return(message, &reply);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         r = sd_bus_message_open_container(reply, 'a', "(ssssuu)");
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         HASHMAP_FOREACH(inhibitor, m->inhibitors, i) {
 
@@ -425,17 +425,17 @@ static int method_list_inhibitors(sd_bus *bus, sd_bus_message *message, void *us
                                           (uint32_t) inhibitor->uid,
                                           (uint32_t) inhibitor->pid);
                 if (r < 0)
-                        return sd_bus_reply_method_errno(message, r, NULL);
+                        return r;
         }
 
         r = sd_bus_message_close_container(reply);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         return sd_bus_send(bus, reply, NULL);
 }
 
-static int method_create_session(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_create_session(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         const char *service, *type, *class, *cseat, *tty, *display, *remote_user, *remote_host;
         uint32_t uid, leader, audit_id = 0;
         _cleanup_free_ char *id = NULL;
@@ -455,17 +455,17 @@ static int method_create_session(sd_bus *bus, sd_bus_message *message, void *use
 
         r = sd_bus_message_read(message, "uussssussbss", &uid, &leader, &service, &type, &class, &cseat, &vtnr, &tty, &display, &remote, &remote_user, &remote_host);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         if (leader == 1)
-                return sd_bus_reply_method_errorf(message, SD_BUS_ERROR_INVALID_ARGS, "Invalid leader PID");
+                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid leader PID");
 
         if (isempty(type))
                 t = _SESSION_TYPE_INVALID;
         else {
                 t = session_type_from_string(type);
                 if (t < 0)
-                        return sd_bus_reply_method_errorf(message, SD_BUS_ERROR_INVALID_ARGS, "Invalid session type %s", type);
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid session type %s", type);
         }
 
         if (isempty(class))
@@ -473,7 +473,7 @@ static int method_create_session(sd_bus *bus, sd_bus_message *message, void *use
         else {
                 c = session_class_from_string(class);
                 if (c < 0)
-                        return sd_bus_reply_method_errorf(message, SD_BUS_ERROR_INVALID_ARGS, "Invalid session class %s", class);
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid session class %s", class);
         }
 
         if (isempty(cseat))
@@ -481,7 +481,7 @@ static int method_create_session(sd_bus *bus, sd_bus_message *message, void *use
         else {
                 seat = hashmap_get(m->seats, cseat);
                 if (!seat)
-                        return sd_bus_reply_method_errorf(message, BUS_ERROR_NO_SUCH_SEAT, "No seat '%s' known", seat);
+                        return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_SEAT, "No seat '%s' known", seat);
         }
 
         if (tty_is_vc(tty)) {
@@ -490,41 +490,41 @@ static int method_create_session(sd_bus *bus, sd_bus_message *message, void *use
                 if (!seat)
                         seat = m->seat0;
                 else if (seat != m->seat0)
-                        return sd_bus_reply_method_errorf(message, SD_BUS_ERROR_INVALID_ARGS, "TTY %s is virtual console but seat %s is not seat0", tty, seat);
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "TTY %s is virtual console but seat %s is not seat0", tty, seat);
 
                 v = vtnr_from_tty(tty);
                 if (v <= 0)
-                        return sd_bus_reply_method_errorf(message, SD_BUS_ERROR_INVALID_ARGS, "Cannot determine VT number from virtual console TTY %s", tty);
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Cannot determine VT number from virtual console TTY %s", tty);
 
                 if (vtnr <= 0)
                         vtnr = (uint32_t) v;
                 else if (vtnr != (uint32_t) v)
-                        return sd_bus_reply_method_errorf(message, SD_BUS_ERROR_INVALID_ARGS, "Specified TTY and VT number do not match");
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Specified TTY and VT number do not match");
 
         } else if (tty_is_console(tty)) {
 
                 if (!seat)
                         seat = m->seat0;
                 else if (seat != m->seat0)
-                        return sd_bus_reply_method_errorf(message, SD_BUS_ERROR_INVALID_ARGS, "Console TTY specified but seat is not seat0");
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Console TTY specified but seat is not seat0");
 
                 if (vtnr != 0)
-                        return sd_bus_reply_method_errorf(message, SD_BUS_ERROR_INVALID_ARGS, "Console TTY specified but VT number is not 0");
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Console TTY specified but VT number is not 0");
         }
 
         if (seat) {
                 if (seat_has_vts(seat)) {
                         if (vtnr > 63)
-                                return sd_bus_reply_method_errorf(message, SD_BUS_ERROR_INVALID_ARGS, "VT number out of range");
+                                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "VT number out of range");
                 } else {
                         if (vtnr != 0)
-                                return sd_bus_reply_method_errorf(message, SD_BUS_ERROR_INVALID_ARGS, "Seat has no VTs but VT number not 0");
+                                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Seat has no VTs but VT number not 0");
                 }
         }
 
         r = sd_bus_message_enter_container(message, 'a', "(sv)");
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         if (t == _SESSION_TYPE_INVALID) {
                 if (!isempty(display))
@@ -547,7 +547,7 @@ static int method_create_session(sd_bus *bus, sd_bus_message *message, void *use
 
                 r = sd_bus_get_owner_pid(bus, sd_bus_message_get_sender(message), (pid_t*) &leader);
                 if (r < 0)
-                        return sd_bus_reply_method_errno(message, r, NULL);
+                        return r;
         }
 
         manager_get_session_by_pid(m, leader, &session);
@@ -561,11 +561,11 @@ static int method_create_session(sd_bus *bus, sd_bus_message *message, void *use
 
                 fifo_fd = session_create_fifo(session);
                 if (fifo_fd < 0)
-                        return sd_bus_reply_method_errno(message, fifo_fd, NULL);
+                        return fifo_fd;
 
                 path = session_bus_path(session);
                 if (!path)
-                        return sd_bus_reply_method_errno(message, -ENOMEM, NULL);
+                        return -ENOMEM;
 
                 return sd_bus_reply_method_return(
                                 message, "soshsub",
@@ -583,7 +583,7 @@ static int method_create_session(sd_bus *bus, sd_bus_message *message, void *use
                 /* Keep our session IDs and the audit session IDs in sync */
 
                 if (asprintf(&id, "%lu", (unsigned long) audit_id) < 0)
-                        return sd_bus_reply_method_errno(message, -ENOMEM, NULL);
+                        return -ENOMEM;
 
                 /* Wut? There's already a session by this name and we
                  * didn't find it above? Weird, then let's not trust
@@ -604,22 +604,18 @@ static int method_create_session(sd_bus *bus, sd_bus_message *message, void *use
                         id = NULL;
 
                         if (asprintf(&id, "c%lu", ++m->session_counter) < 0)
-                                return sd_bus_reply_method_errno(message, -ENOMEM, NULL);
+                                return -ENOMEM;
 
                 } while (hashmap_get(m->sessions, id));
         }
 
         r = manager_add_user_by_uid(m, uid, &user);
-        if (r < 0) {
-                r = sd_bus_reply_method_errno(message, r, NULL);
+        if (r < 0)
                 goto fail;
-        }
 
         r = manager_add_session(m, id, &session);
-        if (r < 0) {
-                r = sd_bus_reply_method_errno(message, r, NULL);
+        if (r < 0)
                 goto fail;
-        }
 
         session_set_user(session, user);
 
@@ -633,7 +629,7 @@ static int method_create_session(sd_bus *bus, sd_bus_message *message, void *use
         if (!isempty(tty)) {
                 session->tty = strdup(tty);
                 if (!session->tty) {
-                        r = sd_bus_reply_method_errno(message, -ENOMEM, NULL);
+                        r = -ENOMEM;
                         goto fail;
                 }
         }
@@ -641,7 +637,7 @@ static int method_create_session(sd_bus *bus, sd_bus_message *message, void *use
         if (!isempty(display)) {
                 session->display = strdup(display);
                 if (!session->display) {
-                        r = sd_bus_reply_method_errno(message, -ENOMEM, NULL);
+                        r = -ENOMEM;
                         goto fail;
                 }
         }
@@ -649,7 +645,7 @@ static int method_create_session(sd_bus *bus, sd_bus_message *message, void *use
         if (!isempty(remote_user)) {
                 session->remote_user = strdup(remote_user);
                 if (!session->remote_user) {
-                        r = sd_bus_reply_method_errno(message, -ENOMEM, NULL);
+                        r = -ENOMEM;
                         goto fail;
                 }
         }
@@ -657,7 +653,7 @@ static int method_create_session(sd_bus *bus, sd_bus_message *message, void *use
         if (!isempty(remote_host)) {
                 session->remote_host = strdup(remote_host);
                 if (!session->remote_host) {
-                        r = sd_bus_reply_method_errno(message, -ENOMEM, NULL);
+                        r = -ENOMEM;
                         goto fail;
                 }
         }
@@ -665,24 +661,20 @@ static int method_create_session(sd_bus *bus, sd_bus_message *message, void *use
         if (!isempty(service)) {
                 session->service = strdup(service);
                 if (!session->service) {
-                        r = sd_bus_reply_method_errno(message, -ENOMEM, NULL);
+                        r = -ENOMEM;
                         goto fail;
                 }
         }
 
         if (seat) {
                 r = seat_attach_session(seat, session);
-                if (r < 0) {
-                        r = sd_bus_reply_method_errno(message, r, NULL);
+                if (r < 0)
                         goto fail;
-                }
         }
 
         r = session_start(session);
-        if (r < 0) {
-                r = sd_bus_reply_method_errno(message, r, NULL);
+        if (r < 0)
                 goto fail;
-        }
 
         session->create_message = sd_bus_message_ref(message);
 
@@ -702,7 +694,7 @@ fail:
         return r;
 }
 
-static int method_release_session(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_release_session(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         Manager *m = userdata;
         Session *session;
         const char *name;
@@ -714,11 +706,11 @@ static int method_release_session(sd_bus *bus, sd_bus_message *message, void *us
 
         r = sd_bus_message_read(message, "s", &name);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         session = hashmap_get(m->sessions, name);
         if (!session)
-                return sd_bus_reply_method_errorf(message, BUS_ERROR_NO_SUCH_SESSION, "No session '%s' known", name);
+                return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_SESSION, "No session '%s' known", name);
 
         /* We use the FIFO to detect stray sessions where the process
            invoking PAM dies abnormally. We need to make sure that
@@ -733,7 +725,7 @@ static int method_release_session(sd_bus *bus, sd_bus_message *message, void *us
         return sd_bus_reply_method_return(message, NULL);
 }
 
-static int method_activate_session(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_activate_session(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         Manager *m = userdata;
         Session *session;
         const char *name;
@@ -745,20 +737,20 @@ static int method_activate_session(sd_bus *bus, sd_bus_message *message, void *u
 
         r = sd_bus_message_read(message, "s", &name);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         session = hashmap_get(m->sessions, name);
         if (!session)
-                return sd_bus_reply_method_errorf(message, BUS_ERROR_NO_SUCH_SESSION, "No session '%s' known", name);
+                return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_SESSION, "No session '%s' known", name);
 
         r = session_activate(session);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         return sd_bus_reply_method_return(message, NULL);
 }
 
-static int method_activate_session_on_seat(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_activate_session_on_seat(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         const char *session_name, *seat_name;
         Manager *m = userdata;
         Session *session;
@@ -774,27 +766,27 @@ static int method_activate_session_on_seat(sd_bus *bus, sd_bus_message *message,
 
         r = sd_bus_message_read(message, "ss", &session_name, &seat_name);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         session = hashmap_get(m->sessions, session_name);
         if (!session)
-                return sd_bus_reply_method_errorf(message, BUS_ERROR_NO_SUCH_SESSION, "No session '%s' known", session_name);
+                return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_SESSION, "No session '%s' known", session_name);
 
         seat = hashmap_get(m->seats, seat_name);
         if (!seat)
-                return sd_bus_reply_method_errorf(message, BUS_ERROR_NO_SUCH_SEAT, "No seat '%s' known", seat_name);
+                return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_SEAT, "No seat '%s' known", seat_name);
 
         if (session->seat != seat)
-                return sd_bus_reply_method_errorf(message, BUS_ERROR_SESSION_NOT_ON_SEAT, "Session %s not on seat %s", session_name, seat_name);
+                return sd_bus_error_setf(error, BUS_ERROR_SESSION_NOT_ON_SEAT, "Session %s not on seat %s", session_name, seat_name);
 
         r = session_activate(session);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         return sd_bus_reply_method_return(message, NULL);
 }
 
-static int method_lock_session(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_lock_session(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         Manager *m = userdata;
         Session *session;
         const char *name;
@@ -806,20 +798,20 @@ static int method_lock_session(sd_bus *bus, sd_bus_message *message, void *userd
 
         r = sd_bus_message_read(message, "s", &name);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         session = hashmap_get(m->sessions, name);
         if (!session)
-                return sd_bus_reply_method_errorf(message, BUS_ERROR_NO_SUCH_SESSION, "No session '%s' known", name);
+                return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_SESSION, "No session '%s' known", name);
 
         r = session_send_lock(session, streq(sd_bus_message_get_member(message), "LockSession"));
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         return sd_bus_reply_method_return(message, NULL);
 }
 
-static int method_lock_sessions(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_lock_sessions(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         Manager *m = userdata;
         int r;
 
@@ -829,12 +821,12 @@ static int method_lock_sessions(sd_bus *bus, sd_bus_message *message, void *user
 
         r = session_send_lock_all(m, streq(sd_bus_message_get_member(message), "LockSessions"));
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         return sd_bus_reply_method_return(message, NULL);
 }
 
-static int method_kill_session(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_kill_session(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         const char *name, *swho;
         Manager *m = userdata;
         Session *session;
@@ -848,31 +840,31 @@ static int method_kill_session(sd_bus *bus, sd_bus_message *message, void *userd
 
         r = sd_bus_message_read(message, "ssi", &name, &swho, &signo);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         if (isempty(swho))
                 who = KILL_ALL;
         else {
                 who = kill_who_from_string(swho);
                 if (who < 0)
-                        return sd_bus_reply_method_errorf(message, SD_BUS_ERROR_INVALID_ARGS, "Invalid kill parameter '%s'", swho);
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid kill parameter '%s'", swho);
         }
 
         if (signo <= 0 || signo >= _NSIG)
-                return sd_bus_reply_method_errorf(message, SD_BUS_ERROR_INVALID_ARGS, "Invalid signal %i", signo);
+                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid signal %i", signo);
 
         session = hashmap_get(m->sessions, name);
         if (!session)
-                return sd_bus_reply_method_errorf(message, BUS_ERROR_NO_SUCH_SESSION, "No session '%s' known", name);
+                return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_SESSION, "No session '%s' known", name);
 
         r = session_kill(session, who, signo);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         return sd_bus_reply_method_return(message, NULL);
 }
 
-static int method_kill_user(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_kill_user(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         Manager *m = userdata;
         uint32_t uid;
         int32_t signo;
@@ -885,23 +877,23 @@ static int method_kill_user(sd_bus *bus, sd_bus_message *message, void *userdata
 
         r = sd_bus_message_read(message, "ui", &uid, &signo);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         if (signo <= 0 || signo >= _NSIG)
-                return sd_bus_reply_method_errorf(message, SD_BUS_ERROR_INVALID_ARGS, "Invalid signal %i", signo);
+                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid signal %i", signo);
 
         user = hashmap_get(m->users, ULONG_TO_PTR((unsigned long) uid));
         if (!user)
-                return sd_bus_reply_method_errorf(message, BUS_ERROR_NO_SUCH_USER, "No user '%lu' known or logged in", (unsigned long) uid);
+                return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_USER, "No user '%lu' known or logged in", (unsigned long) uid);
 
         r = user_kill(user, signo);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         return sd_bus_reply_method_return(message, NULL);
 }
 
-static int method_terminate_session(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_terminate_session(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         Manager *m = userdata;
         const char *name;
         Session *session;
@@ -913,20 +905,20 @@ static int method_terminate_session(sd_bus *bus, sd_bus_message *message, void *
 
         r = sd_bus_message_read(message, "s", &name);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         session = hashmap_get(m->sessions, name);
         if (!session)
-                return sd_bus_reply_method_errorf(message, BUS_ERROR_NO_SUCH_SESSION, "No session '%s' known", name);
+                return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_SESSION, "No session '%s' known", name);
 
         r = session_stop(session);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         return sd_bus_reply_method_return(message, NULL);
 }
 
-static int method_terminate_user(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_terminate_user(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         Manager *m = userdata;
         uint32_t uid;
         User *user;
@@ -938,20 +930,20 @@ static int method_terminate_user(sd_bus *bus, sd_bus_message *message, void *use
 
         r = sd_bus_message_read(message, "u", &uid);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         user = hashmap_get(m->users, ULONG_TO_PTR((unsigned long) uid));
         if (!user)
-                return sd_bus_reply_method_errorf(message, BUS_ERROR_NO_SUCH_USER, "No user '%lu' known or logged in", (unsigned long) uid);
+                return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_USER, "No user '%lu' known or logged in", (unsigned long) uid);
 
         r = user_stop(user);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         return sd_bus_reply_method_return(message, NULL);
 }
 
-static int method_terminate_seat(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_terminate_seat(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         Manager *m = userdata;
         const char *name;
         Seat *seat;
@@ -963,21 +955,20 @@ static int method_terminate_seat(sd_bus *bus, sd_bus_message *message, void *use
 
         r = sd_bus_message_read(message, "s", &name);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         seat = hashmap_get(m->seats, name);
         if (!seat)
-                return sd_bus_reply_method_errorf(message, BUS_ERROR_NO_SUCH_SEAT, "No seat '%s' known", name);
+                return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_SEAT, "No seat '%s' known", name);
 
         r = seat_stop_sessions(seat);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         return sd_bus_reply_method_return(message, NULL);
 }
 
-static int method_set_user_linger(sd_bus *bus, sd_bus_message *message, void *userdata) {
-        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+static int method_set_user_linger(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         _cleanup_free_ char *cc = NULL;
         Manager *m = userdata;
         int b, r;
@@ -992,22 +983,22 @@ static int method_set_user_linger(sd_bus *bus, sd_bus_message *message, void *us
 
         r = sd_bus_message_read(message, "ubb", &uid, &b, &interactive);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         errno = 0;
         pw = getpwuid(uid);
         if (!pw)
-                return sd_bus_reply_method_errno(message, errno ? errno : ENOENT, NULL);
+                return errno ? -errno : -ENOENT;
 
         r = bus_verify_polkit_async(bus,
                                     &m->polkit_registry,
                                     message,
                                     "org.freedesktop.login1.set-user-linger",
                                     interactive,
-                                    &error,
+                                    error,
                                     method_set_user_linger, m);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, &error);
+                return r;
         if (r == 0)
                 return 1; /* No authorization for now, but the async polkit stuff will call us again when it has it */
 
@@ -1015,11 +1006,11 @@ static int method_set_user_linger(sd_bus *bus, sd_bus_message *message, void *us
 
         r = mkdir_safe_label("/var/lib/systemd/linger", 0755, 0, 0);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         cc = cescape(pw->pw_name);
         if (!cc)
-                return sd_bus_reply_method_errno(message, ENOMEM, NULL);
+                return -ENOMEM;
 
         path = strappenda("/var/lib/systemd/linger/", cc);
         if (b) {
@@ -1027,7 +1018,7 @@ static int method_set_user_linger(sd_bus *bus, sd_bus_message *message, void *us
 
                 r = touch(path);
                 if (r < 0)
-                        return sd_bus_reply_method_errno(message, r, NULL);
+                        return r;
 
                 if (manager_add_user_by_uid(m, uid, &u) >= 0)
                         user_start(u);
@@ -1037,7 +1028,7 @@ static int method_set_user_linger(sd_bus *bus, sd_bus_message *message, void *us
 
                 r = unlink(path);
                 if (r < 0 && errno != ENOENT)
-                        return sd_bus_reply_method_errno(message, errno, NULL);
+                        return -errno;
 
                 u = hashmap_get(m->users, ULONG_TO_PTR((unsigned long) uid));
                 if (u)
@@ -1178,8 +1169,7 @@ static int flush_devices(Manager *m) {
         return trigger_device(m, NULL);
 }
 
-static int method_attach_device(sd_bus *bus, sd_bus_message *message, void *userdata) {
-        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+static int method_attach_device(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         const char *sysfs, *seat;
         Manager *m = userdata;
         int interactive, r;
@@ -1190,35 +1180,34 @@ static int method_attach_device(sd_bus *bus, sd_bus_message *message, void *user
 
         r = sd_bus_message_read(message, "ssb", &seat, &sysfs, &interactive);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         if (!path_startswith(sysfs, "/sys"))
-                return sd_bus_reply_method_errorf(message, SD_BUS_ERROR_INVALID_ARGS, "Path %s is not in /sys", sysfs);
+                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Path %s is not in /sys", sysfs);
 
         if (!seat_name_is_valid(seat))
-                return sd_bus_reply_method_errorf(message, SD_BUS_ERROR_INVALID_ARGS, "Seat %s is not valid", seat);
+                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Seat %s is not valid", seat);
 
         r = bus_verify_polkit_async(bus,
                                     &m->polkit_registry,
                                     message,
                                     "org.freedesktop.login1.attach-device",
                                     interactive,
-                                    &error,
+                                    error,
                                     method_attach_device, m);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, &error);
+                return r;
         if (r == 0)
                 return 1; /* No authorization for now, but the async polkit stuff will call us again when it has it */
 
         r = attach_device(m, seat, sysfs);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         return sd_bus_reply_method_return(message, NULL);
 }
 
-static int method_flush_devices(sd_bus *bus, sd_bus_message *message, void *userdata) {
-        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+static int method_flush_devices(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         Manager *m = userdata;
         int interactive, r;
 
@@ -1228,23 +1217,23 @@ static int method_flush_devices(sd_bus *bus, sd_bus_message *message, void *user
 
         r = sd_bus_message_read(message, "b", &interactive);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         r = bus_verify_polkit_async(bus,
                                     &m->polkit_registry,
                                     message,
                                     "org.freedesktop.login1.flush-devices",
                                     interactive,
-                                    &error,
+                                    error,
                                     method_flush_devices, m);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, &error);
+                return r;
         if (r == 0)
                 return 1; /* No authorization for now, but the async polkit stuff will call us again when it has it */
 
         r = flush_devices(m);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, &error);
+                return r;
 
         return sd_bus_reply_method_return(message, NULL);
 }
@@ -1432,9 +1421,9 @@ static int method_do_shutdown_or_sleep(
                 const char *action_multiple_sessions,
                 const char *action_ignore_inhibit,
                 const char *sleep_verb,
-                sd_bus_message_handler_t method) {
+                sd_bus_message_handler_t method,
+                sd_bus_error *error) {
 
-        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
         bool multiple_sessions, blocked;
         int interactive, r;
         uid_t uid;
@@ -1451,61 +1440,61 @@ static int method_do_shutdown_or_sleep(
 
         r = sd_bus_message_read(message, "b", &interactive);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         /* Don't allow multiple jobs being executed at the same time */
         if (m->action_what)
-                return sd_bus_reply_method_errorf(message, BUS_ERROR_OPERATION_IN_PROGRESS, "There's already a shutdown or sleep operation in progress");
+                return sd_bus_error_setf(error, BUS_ERROR_OPERATION_IN_PROGRESS, "There's already a shutdown or sleep operation in progress");
 
         if (sleep_verb) {
                 r = can_sleep(sleep_verb);
                 if (r < 0)
-                        return sd_bus_reply_method_errno(message, r, NULL);
+                        return r;
 
                 if (r == 0)
-                        return sd_bus_reply_method_errorf(message, BUS_ERROR_SLEEP_VERB_NOT_SUPPORTED, "Sleep verb not supported");
+                        return sd_bus_error_setf(error, BUS_ERROR_SLEEP_VERB_NOT_SUPPORTED, "Sleep verb not supported");
         }
 
         r = sd_bus_get_owner_uid(m->bus, sd_bus_message_get_sender(message), &uid);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         r = have_multiple_sessions(m, uid);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         multiple_sessions = r > 0;
         blocked = manager_is_inhibited(m, w, INHIBIT_BLOCK, NULL, false, true, uid);
 
         if (multiple_sessions) {
                 r = bus_verify_polkit_async(m->bus, &m->polkit_registry, message,
-                                            action_multiple_sessions, interactive, &error, method, m);
+                                            action_multiple_sessions, interactive, error, method, m);
                 if (r < 0)
-                        return sd_bus_reply_method_errno(message, r, &error);
+                        return r;
         }
 
         if (blocked) {
                 r = bus_verify_polkit_async(m->bus, &m->polkit_registry, message,
-                                            action_ignore_inhibit, interactive, &error, method, m);
+                                            action_ignore_inhibit, interactive, error, method, m);
                 if (r < 0)
-                        return sd_bus_reply_method_errno(message, r, &error);
+                        return r;
         }
 
         if (!multiple_sessions && !blocked) {
                 r = bus_verify_polkit_async(m->bus, &m->polkit_registry, message,
-                                            action, interactive, &error, method, m);
+                                            action, interactive, error, method, m);
                 if (r < 0)
-                        return sd_bus_reply_method_errno(message, r, &error);
+                        return r;
         }
 
-        r = bus_manager_shutdown_or_sleep_now_or_later(m, unit_name, w, &error);
+        r = bus_manager_shutdown_or_sleep_now_or_later(m, unit_name, w, error);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, &error);
+                return r;
 
         return sd_bus_reply_method_return(message, NULL);
 }
 
-static int method_poweroff(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_poweroff(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         Manager *m = userdata;
 
         return method_do_shutdown_or_sleep(
@@ -1516,10 +1505,11 @@ static int method_poweroff(sd_bus *bus, sd_bus_message *message, void *userdata)
                         "org.freedesktop.login1.power-off-multiple-sessions",
                         "org.freedesktop.login1.power-off-ignore-inhibit",
                         NULL,
-                        method_poweroff);
+                        method_poweroff,
+                        error);
 }
 
-static int method_reboot(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_reboot(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         Manager *m = userdata;
 
         return method_do_shutdown_or_sleep(
@@ -1530,10 +1520,11 @@ static int method_reboot(sd_bus *bus, sd_bus_message *message, void *userdata) {
                         "org.freedesktop.login1.reboot-multiple-sessions",
                         "org.freedesktop.login1.reboot-ignore-inhibit",
                         NULL,
-                        method_reboot);
+                        method_reboot,
+                        error);
 }
 
-static int method_suspend(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_suspend(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         Manager *m = userdata;
 
         return method_do_shutdown_or_sleep(
@@ -1544,10 +1535,11 @@ static int method_suspend(sd_bus *bus, sd_bus_message *message, void *userdata)
                         "org.freedesktop.login1.suspend-multiple-sessions",
                         "org.freedesktop.login1.suspend-ignore-inhibit",
                         "suspend",
-                        method_suspend);
+                        method_suspend,
+                        error);
 }
 
-static int method_hibernate(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_hibernate(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         Manager *m = userdata;
 
         return method_do_shutdown_or_sleep(
@@ -1558,10 +1550,11 @@ static int method_hibernate(sd_bus *bus, sd_bus_message *message, void *userdata
                         "org.freedesktop.login1.hibernate-multiple-sessions",
                         "org.freedesktop.login1.hibernate-ignore-inhibit",
                         "hibernate",
-                        method_hibernate);
+                        method_hibernate,
+                        error);
 }
 
-static int method_hybrid_sleep(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_hybrid_sleep(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         Manager *m = userdata;
 
         return method_do_shutdown_or_sleep(
@@ -1572,7 +1565,8 @@ static int method_hybrid_sleep(sd_bus *bus, sd_bus_message *message, void *userd
                         "org.freedesktop.login1.hibernate-multiple-sessions",
                         "org.freedesktop.login1.hibernate-ignore-inhibit",
                         "hybrid-sleep",
-                        method_hybrid_sleep);
+                        method_hybrid_sleep,
+                        error);
 }
 
 static int method_can_shutdown_or_sleep(
@@ -1582,9 +1576,9 @@ static int method_can_shutdown_or_sleep(
                 const char *action,
                 const char *action_multiple_sessions,
                 const char *action_ignore_inhibit,
-                const char *sleep_verb) {
+                const char *sleep_verb,
+                sd_bus_error *error) {
 
-        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
         bool multiple_sessions, challenge, blocked;
         const char *result = NULL;
         uid_t uid;
@@ -1601,26 +1595,26 @@ static int method_can_shutdown_or_sleep(
         if (sleep_verb) {
                 r = can_sleep(sleep_verb);
                 if (r < 0)
-                        return sd_bus_reply_method_errno(message, r, NULL);
+                        return r;
                 if (r == 0)
                         return sd_bus_reply_method_return(message, "s", "na");
         }
 
         r = sd_bus_get_owner_uid(m->bus, sd_bus_message_get_sender(message), &uid);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         r = have_multiple_sessions(m, uid);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         multiple_sessions = r > 0;
         blocked = manager_is_inhibited(m, w, INHIBIT_BLOCK, NULL, false, true, uid);
 
         if (multiple_sessions) {
-                r = bus_verify_polkit(m->bus, message, action_multiple_sessions, false, &challenge, &error);
+                r = bus_verify_polkit(m->bus, message, action_multiple_sessions, false, &challenge, error);
                 if (r < 0)
-                        return sd_bus_reply_method_errno(message, r, &error);
+                        return r;
 
                 if (r > 0)
                         result = "yes";
@@ -1631,9 +1625,9 @@ static int method_can_shutdown_or_sleep(
         }
 
         if (blocked) {
-                r = bus_verify_polkit(m->bus, message, action_ignore_inhibit, false, &challenge, &error);
+                r = bus_verify_polkit(m->bus, message, action_ignore_inhibit, false, &challenge, error);
                 if (r < 0)
-                        return sd_bus_reply_method_errno(message, r, &error);
+                        return r;
 
                 if (r > 0 && !result)
                         result = "yes";
@@ -1647,9 +1641,9 @@ static int method_can_shutdown_or_sleep(
                 /* If neither inhibit nor multiple sessions
                  * apply then just check the normal policy */
 
-                r = bus_verify_polkit(m->bus, message, action, false, &challenge, &error);
+                r = bus_verify_polkit(m->bus, message, action, false, &challenge, error);
                 if (r < 0)
-                        return sd_bus_reply_method_errno(message, r, &error);
+                        return r;
 
                 if (r > 0)
                         result = "yes";
@@ -1662,7 +1656,7 @@ static int method_can_shutdown_or_sleep(
         return sd_bus_reply_method_return(message, "s", result);
 }
 
-static int method_can_poweroff(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_can_poweroff(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         Manager *m = userdata;
 
         return method_can_shutdown_or_sleep(
@@ -1671,10 +1665,11 @@ static int method_can_poweroff(sd_bus *bus, sd_bus_message *message, void *userd
                         "org.freedesktop.login1.power-off",
                         "org.freedesktop.login1.power-off-multiple-sessions",
                         "org.freedesktop.login1.power-off-ignore-inhibit",
-                        NULL);
+                        NULL,
+                        error);
 }
 
-static int method_can_reboot(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_can_reboot(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         Manager *m = userdata;
 
         return method_can_shutdown_or_sleep(
@@ -1683,10 +1678,11 @@ static int method_can_reboot(sd_bus *bus, sd_bus_message *message, void *userdat
                         "org.freedesktop.login1.reboot",
                         "org.freedesktop.login1.reboot-multiple-sessions",
                         "org.freedesktop.login1.reboot-ignore-inhibit",
-                        NULL);
+                        NULL,
+                        error);
 }
 
-static int method_can_suspend(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_can_suspend(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         Manager *m = userdata;
 
         return method_can_shutdown_or_sleep(
@@ -1695,10 +1691,11 @@ static int method_can_suspend(sd_bus *bus, sd_bus_message *message, void *userda
                         "org.freedesktop.login1.suspend",
                         "org.freedesktop.login1.suspend-multiple-sessions",
                         "org.freedesktop.login1.suspend-ignore-inhibit",
-                        "suspend");
+                        "suspend",
+                        error);
 }
 
-static int method_can_hibernate(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_can_hibernate(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         Manager *m = userdata;
 
         return method_can_shutdown_or_sleep(
@@ -1707,10 +1704,11 @@ static int method_can_hibernate(sd_bus *bus, sd_bus_message *message, void *user
                         "org.freedesktop.login1.hibernate",
                         "org.freedesktop.login1.hibernate-multiple-sessions",
                         "org.freedesktop.login1.hibernate-ignore-inhibit",
-                        "hibernate");
+                        "hibernate",
+                        error);
 }
 
-static int method_can_hybrid_sleep(sd_bus *bus, sd_bus_message *message, void *userdata) {
+static int method_can_hybrid_sleep(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         Manager *m = userdata;
 
         return method_can_shutdown_or_sleep(
@@ -1719,11 +1717,11 @@ static int method_can_hybrid_sleep(sd_bus *bus, sd_bus_message *message, void *u
                         "org.freedesktop.login1.hibernate",
                         "org.freedesktop.login1.hibernate-multiple-sessions",
                         "org.freedesktop.login1.hibernate-ignore-inhibit",
-                        "hybrid-sleep");
+                        "hybrid-sleep",
+                        error);
 }
 
-static int method_inhibit(sd_bus *bus, sd_bus_message *message, void *userdata) {
-        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+static int method_inhibit(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         const char *who, *why, *what, *mode;
         _cleanup_free_ char *id = NULL;
         _cleanup_close_ int fifo_fd = -1;
@@ -1741,26 +1739,26 @@ static int method_inhibit(sd_bus *bus, sd_bus_message *message, void *userdata)
 
         r = sd_bus_message_read(message, "ssss", &what, &who, &why, &mode);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         w = inhibit_what_from_string(what);
         if (w <= 0)
-                return sd_bus_reply_method_errorf(message, SD_BUS_ERROR_INVALID_ARGS, "Invalid what specification %s", what);
+                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid what specification %s", what);
 
         mm = inhibit_mode_from_string(mode);
         if (mm < 0)
-                return sd_bus_reply_method_errorf(message, SD_BUS_ERROR_INVALID_ARGS, "Invalid mode specification %s", mode);
+                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid mode specification %s", mode);
 
         /* Delay is only supported for shutdown/sleep */
         if (mm == INHIBIT_DELAY && (w & ~(INHIBIT_SHUTDOWN|INHIBIT_SLEEP)))
-                return sd_bus_reply_method_errorf(message, SD_BUS_ERROR_INVALID_ARGS, "Delay inhibitors only supported for shutdown and sleep");
+                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Delay inhibitors only supported for shutdown and sleep");
 
         /* Don't allow taking delay locks while we are already
          * executing the operation. We shouldn't create the impression
          * that the lock was successful if the machine is about to go
          * down/suspend any moment. */
         if (m->action_what & w)
-                return sd_bus_reply_method_errorf(message, BUS_ERROR_OPERATION_IN_PROGRESS, "The operation inhibition has been requested for is already running");
+                return sd_bus_error_setf(error, BUS_ERROR_OPERATION_IN_PROGRESS, "The operation inhibition has been requested for is already running");
 
         r = bus_verify_polkit_async(bus, &m->polkit_registry, message,
                                     w == INHIBIT_SHUTDOWN             ? (mm == INHIBIT_BLOCK ? "org.freedesktop.login1.inhibit-block-shutdown" : "org.freedesktop.login1.inhibit-delay-shutdown") :
@@ -1770,32 +1768,32 @@ static int method_inhibit(sd_bus *bus, sd_bus_message *message, void *userdata)
                                     w == INHIBIT_HANDLE_SUSPEND_KEY   ? "org.freedesktop.login1.inhibit-handle-suspend-key" :
                                     w == INHIBIT_HANDLE_HIBERNATE_KEY ? "org.freedesktop.login1.inhibit-handle-hibernate-key" :
                                                                         "org.freedesktop.login1.inhibit-handle-lid-switch",
-                                    false, &error, method_inhibit, m);
+                                    false, error, method_inhibit, m);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, &error);
+                return r;
         if (r == 0)
                 return 1; /* No authorization for now, but the async polkit stuff will call us again when it has it */
 
         r = sd_bus_get_owner_uid(m->bus, sd_bus_message_get_sender(message), &uid);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         r = sd_bus_get_owner_pid(m->bus, sd_bus_message_get_sender(message), &pid);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         do {
                 free(id);
                 id = NULL;
 
                 if (asprintf(&id, "%lu", ++m->inhibit_counter) < 0)
-                        return sd_bus_reply_method_errno(message, -ENOMEM, NULL);
+                        return -ENOMEM;
 
         } while (hashmap_get(m->inhibitors, id));
 
         r = manager_add_inhibitor(m, id, &i);
         if (r < 0)
-                return sd_bus_reply_method_errno(message, r, NULL);
+                return r;
 
         i->what = w;
         i->mode = mm;
@@ -1805,13 +1803,13 @@ static int method_inhibit(sd_bus *bus, sd_bus_message *message, void *userdata)
         i->who = strdup(who);
 
         if (!i->why || !i->who) {
-                r = sd_bus_reply_method_errno(message, -ENOMEM, NULL);
+                r = -ENOMEM;
                 goto fail;
         }
 
         fifo_fd = inhibitor_create_fifo(i);
         if (fifo_fd < 0) {
-                r = sd_bus_reply_method_errno(message, fifo_fd, NULL);
+                r = fifo_fd;
                 goto fail;
         }
 
@@ -1897,7 +1895,7 @@ const sd_bus_vtable manager_vtable[] = {
         SD_BUS_VTABLE_END
 };
 
-int match_job_removed(sd_bus *bus, sd_bus_message *message, void *userdata) {
+int match_job_removed(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         const char *path, *result, *unit;
         Manager *m = userdata;
         Session *session;
@@ -1911,8 +1909,8 @@ int match_job_removed(sd_bus *bus, sd_bus_message *message, void *userdata) {
 
         r = sd_bus_message_read(message, "uoss", &id, &path, &unit, &result);
         if (r < 0) {
-                log_error("Failed to parse JobRemoved message: %s", strerror(-r));
-                return 0;
+                bus_log_parse_error(r);
+                return r;
         }
 
         if (m->action_job && streq(m->action_job, path)) {
@@ -1940,10 +1938,10 @@ int match_job_removed(sd_bus *bus, sd_bus_message *message, void *userdata) {
                         if (streq(result, "done"))
                                 session_send_create_reply(session, NULL);
                         else {
-                                _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+                                _cleanup_bus_error_free_ sd_bus_error e = SD_BUS_ERROR_NULL;
 
-                                sd_bus_error_setf(&error, BUS_ERROR_JOB_FAILED, "Start job for unit %s failed with '%s'", unit, result);
-                                session_send_create_reply(session, &error);
+                                sd_bus_error_setf(&e, BUS_ERROR_JOB_FAILED, "Start job for unit %s failed with '%s'", unit, result);
+                                session_send_create_reply(session, &e);
                         }
                 } else
                         session_save(session);
@@ -1971,7 +1969,7 @@ int match_job_removed(sd_bus *bus, sd_bus_message *message, void *userdata) {
         return 0;
 }
 
-int match_unit_removed(sd_bus *bus, sd_bus_message *message, void *userdata) {
+int match_unit_removed(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         const char *path, *unit;
         Manager *m = userdata;
         Session *session;
@@ -1984,8 +1982,8 @@ int match_unit_removed(sd_bus *bus, sd_bus_message *message, void *userdata) {
 
         r = sd_bus_message_read(message, "so", &unit, &path);
         if (r < 0) {
-                log_error("Failed to parse UnitRemoved message: %s", strerror(-r));
-                return 0;
+                bus_log_parse_error(r);
+                return r;
         }
 
         session = hashmap_get(m->session_units, unit);
@@ -1999,12 +1997,13 @@ int match_unit_removed(sd_bus *bus, sd_bus_message *message, void *userdata) {
         return 0;
 }
 
-int match_properties_changed(sd_bus *bus, sd_bus_message *message, void *userdata) {
+int match_properties_changed(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         _cleanup_free_ char *unit = NULL;
         Manager *m = userdata;
         const char *path;
         Session *session;
         User *user;
+        int r;
 
         assert(bus);
         assert(message);
@@ -2014,9 +2013,9 @@ int match_properties_changed(sd_bus *bus, sd_bus_message *message, void *userdat
         if (!path)
                 return 0;
 
-        unit_name_from_dbus_path(path, &unit);
-        if (!unit)
-                return 0;
+        r = unit_name_from_dbus_path(path, &unit);
+        if (r < 0)
+                return r;
 
         session = hashmap_get(m->session_units, unit);
         if (session)
@@ -2029,7 +2028,7 @@ int match_properties_changed(sd_bus *bus, sd_bus_message *message, void *userdat
         return 0;
 }
 
-int match_reloading(sd_bus *bus, sd_bus_message *message, void *userdata) {
+int match_reloading(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         Manager *m = userdata;
         Session *session;
         Iterator i;
@@ -2039,8 +2038,8 @@ int match_reloading(sd_bus *bus, sd_bus_message *message, void *userdata) {
 
         r = sd_bus_message_read(message, "b", &b);
         if (r < 0) {
-                log_error("Failed to parse Reloading message: %s", strerror(-r));
-                return 0;
+                bus_log_parse_error(r);
+                return r;
         }
 
         if (b)
@@ -2055,7 +2054,7 @@ int match_reloading(sd_bus *bus, sd_bus_message *message, void *userdata) {
         return 0;
 }
 
-int match_name_owner_changed(sd_bus *bus, sd_bus_message *message, void *userdata) {
+int match_name_owner_changed(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
         const char *name, *old, *new;
         Manager *m = userdata;
         Session *session;
@@ -2067,8 +2066,8 @@ int match_name_owner_changed(sd_bus *bus, sd_bus_message *message, void *userdat
 
         r = sd_bus_message_read(message, "sss", &name, &old, &new);
         if (r < 0) {
-                log_error("Failed to parse NameOwnerChanged message: %s", strerror(-r));
-                return 0;
+                bus_log_parse_error(r);
+                return r;
         }
 
         if (isempty(old) || !isempty(new))